Let-off for looms



Dec. 10, 1929. R HOLMES 1,739,232

' LET-OFF F01; LOOMS v Filed Dec. 6, 1927 Patented Dec. 10, 1929 ELBEIDGE R. -HOLMES," OF WORCESTER, MASSACHUSETTS, ASSIGNOR TO CROMPTON mA'ssAcHus'nrTs 2 ts; KNOWLES-LOOM'WORKS, or WORCESTER,@MASSACHUSETTS, A- conron-A'rion or LET-OFF FOR LOOMS Application filed December 6, 192?. Serial No. 238,152.

This invention relates to improvements in let-oifs for looms and it-is the general object of the invention to provide means for tightening the warp at the time of beat-up of the lay .to hold the warp threads under sufficient tension to insure-tight-cloth.

ln theweaving of multi-ply cotton straps or belting it is not uncommon to employ a so-ca;lled.=closed shed loom wherein all of the warp threads are brought to mid position at eachgbea't lpofthe loom. In such a 100111 the warp is slackenedat the time of beat-up because of the central position of the warp threads. If the layattempts to beat in filling under-this condition of slackened warp it is found that thepicks will not be incorporated intothe-cloth under the proper tension with the result that the fabric; is-soft and weak. It is an i-mportant'obje'ct of my present invention to provide "means for. moving the warp threadsrearwardly a slight amount on eachbat-upoff the lay so as to take up slackness in the warp threads.

'It is :foiind,'lioWever, -that it is insufficient .merel'yto move the threads backwardly by meansof amovable whip rollunless further provision-xbe made to prevent ;an advance movement of thewar-pthreads from the warp beam'or deli-very drum-and it is accordingly 1a furtherobjecteiof m invention not only to move't-he whip rOIl rearvvardlybutat the same timetoi placeadditional tension on the warp delivery means to prevent rotation of the same}: V

ltis a more detailed object of my present invention to accomplish the aforesaid results by the use of a lever oscillated every pick of the .loom and connectedto the whip rolland also'the let-off and effective to act on these "members when th e lay beats up, the lever 'Pf'ferably being operated by a-c'am'.

IWith these arid otlier objects in view which will appearas the description proceeds, my iav ntieni resides in the combination and arsetforthinthe claims.

In the accompanying drawings, wherein I have show-n a convenient embodiment of my rangein 'ent of parts hereinafter described and invention; I V

Figfli-s a vertical section of the loom looking from the center toward one side and showing my invention applied thereto with the parts in the position they assume when the lay is in rear position,

Fig. 2 is a View similar to Fig. l but with the parts moved to apply increased resistance to the movement of the warp delivery means and to move the whip roll rearwardly so that thelwarp is held against advance movement, anc

Fig. 3 is a detailed top plan view of one end of the device taken in the direction of arrow 3, Fig. 1. v I

Referring-to the drawings, the loom frame 10 has a breast beam 11 over which the fabric F extends. Alay L is moved-by the usual mechanism not shown back and forth to beat the filling-laid by the shuttle S into the fell ofth'e cloth 12. The warp l/V is controlled hy the harnesses H which may be driven in any manner preferably operated on the socalledclosed shed principle, that is, cometo mid position'o'n each pick-of the 100m when the lay iL is inits foremost positions -Sec11red' tothe rear -end of the frame 10 at each ;sidethereof* arebraokets 13 held in anymanner to cross girts l-of'theloom only one bracket beingshown and said brackets provide support for a warp delivery means which in the present instance is a drum :15 mounted on a shaft 16: Said drum is provided with a friction head 17 around "which extends-a-flexible friction element 18 the forward end'of' which is adjustably heldby an eye bolt 19'and the rear'end ofcwh-ich is connected as at=20 to a lever. 21 pivotedt-o one of the brackets as at '22. A weight 23 is mounted OIItl-l rearend of the lever 21 and acts normal'ly' to "tension the flexible member 18.

, WVhile the drawings show' but one friction cal ings.

Each bell crank lever is provided with a substantially horizontal rearwardly projecting arm 32 to which is connected as at 33 the upper end of an adjustable link 34. Said levers 31 move about a rod 35 carried by the brackets 13.

A bearing stand 36 is secured to one of the girts l4 and has secured therein a pivot pin 37 on which is mounted for limited oscillation a tensioning lever 38. The upper forward end of said lever is provided with a roll 39 to cooperate with a cam 40 secured to the bottom shaft 41 of the loom. In the present instance the loom is of the so-called equal geared type so that the bottom shaft rotates respectively, which receive studs 47 and 48,

respectively, secured to the horizontal arm 42. It is to be understood that if two flexible bands 18 are employed there may also be employed two of the levers 38 and all the parts associated therewith.

The warp after passing around the whip roll 30, extends under a fixed rod 49 carried by the fixed. structure of the loom frame, over the drum 15 and over a second fixed rod 50,

.and under the rod 51, extending rearwardly to the creel or other source of supply.

In operation, when the lay is in its rearward position, the shaft 41 will be so placed that the roll 39 will be on the low part 52 of i the cam so that the horizontal arm 42 may be in its raised position and the flexible strap 18 is strained merely by the weight of the lever 21, weight 23 and the link 43. Under these conditions also the whip roll 30 will be in its k forward position 'or'to the left as viewed in Fig. 1. During the cycle of the loom the lay will move forwardly to beat in the filling. In the type of-loom to which the invention more particularly relates the harnesses H will all be in mid or intermediate position when the lay is at its extremeforward position so that all of thewarp threads are slack. At

' this time, however, the high point 53 of the cam 40 is operative to rock the lever 38 in a clockwise direction from the position shown in Fig. 1 to that shown in Fig. 2. The effect of this movement is twofold, namely, link 43 places lever 21 under an additional strain over that created normally by the weight 23, and link 34 moves the whip'roll 30 to the rearward position shown .in Fig. 2. The warps will therefore assume the substantially horizontal position shown in'Fig. 2 with no slackness due to the fact that the whip roll has been'moved rearwardly a suflicient distance beat-up. This ginsures holding; the warp 1 threads against advance 'movement; The cam causes the flexible band 18yto stretch somewhat but not sufiiciently to cause a permanent set therein. After the beat-up while the lay is movingrearwardly the point 53 will turn away from the roll 39 and the whip roll 30 may move forwardly and the strain on the drum be reduced tonormal so that the necessary advance of the warp due to the take-up mechanismnot shown may be provided for.

From the foregoing it will be seen that I have provided a simple means for moving the whip rollto take up slack in the warp of a closed shed loom and at the same time provide means for preventing advance movement of the warp threads when the lay beats in the filling. It will also be seen that I have provided means whereby a single lever is effective-to move the whip roll to take up slack and at the same time apply additional tension to the warp delivery means.

Having thus described my invention it will be apparent that changes and modifications may be made thereinby those skilled in the art without departing from thespirit and scope of the invention and I do not wish to be limited to the details herein disclosed, but

what I claim is:

1.' In a let-off motion for a loom'having a lay to beat in the filling, a lever oscillated each pick of the loom when the lay is in its. beating-up position, a whip roll movable toward and from the lay, a normally resisted warp delivery means acting independentlyfl of the whip roll at all times, and connections between said lever and the whiproll and between said lever and the warp delivery means to move the whip roll rearwardly and also to.

rock said lever each pick of'the loom, a warp delivery means subjected to. a given resistance throughout the major part of the cycle of the pick, a whip roll movable toward and from the lay, connections between the lever and the whip roll to move the latter rearwardly at the timeiof beat-up of the lay,

and additional connections acting independently of the whip roll between the lever and the warp delivery means to offer additional 2. In a let-off motion for a 100m having a" .lay to beat in the filling, a lever, a cam to resistance to the movement of the latter at the time of beat-up of the lay.

3. In a let-off motion for a loom having a lay to beat in the filling, a warp delivery means, a flexible frictional element cooperating with the warp delivery means tending to resist movement of the latter at all times, means to place said flexible resilient means under a given tension throughout the greater part of the cycle of the pick of the loom while the lay is in its rearward position, a whip roll mounted for movement toward and from the lay, a lever, a cam to rock the lever when the lay is in its extreme forward position, connections between the lever and the whip roll to move the latter rearwardly when the lay is in its extreme forward position, and additional means connecting'the lever and the flexible frictional element to place the latter under additional strain when the lay is in its extreme forward position, said additional means acting independently of the whip roll.

l. In a let-off motion for a loom having a lay to beat in the filling, a warp delivery means, a whip roll movable toward and from the lay, a tensioning lever having a regularly recurring operative movement in a given direction, connections between the Whip roll and the tensioning lever whereby the latter is efiective to move the whip roll away from the lay and whereby the whip roll when acted upon by the warp to move toward the lay tends to move the tensioning'lever in a direction opposite to the given movement, means independent of the tensioning lever to exert a normal tension on the warp delivery means, and connections between the latter and the tensioning member to decrease the tension on the warp delivery means when the tensioning lever moves in a given direction.

5. In a let-off motion for a loom havin a lay to beat in the filling, a whip roll mova 1e toward and from the lay, a warp delivery means, a tensioning lever having; a positive movement in a given direction at the time the lay moves to its forward position, connections between the tensioning lever and the warp delivery means to increase the resistance offered the warp when the lever moves in the given direction, and other connections between the tensioning lever and the whip roll to cause the latter to move away from the lay when the tensioning lever moves in the given direction, and said other connections tending to I move the lever in a direction opposite to the given movement when the whip roll is acted upon by the warp threads to move toward the lay, the first named connections being ineffective to transmit a force from the tensioning lever to the warp delivery means when said lever is moving in a direction opposite to the aforesaid given direction.

6. In a let-off motion for a loom having a lay to beat in the filling, a tensioning lever movable positively in a given direction when the lay is in forward position, a warp delivery means, a second means to exert a normal resistance to movement of the warp delivery means, a whip roll movable toward and from the lay, connections between the lever and the second named means capable of increasing the normal resistance when the lever moves in the given direction and ineffective to lessen the normal resistance offered by said second named means when the lever moves in the opposite direction, and connections between said lever and the whip roll to move the latter rearwardly when the lever moves in the said given direction.

7. In a let-off for a loom having a lay movable to beat in the filling, a whip roll movable toward and from the lay, means to offer a normal resistance to the feeding movement of the warp threads over the whip roll and toward the lay, a regularly moving member having a motion in a given direction at the time the lay approaches its forward position, connections between said member and the whip roll to move the latter rearwardly and also to increase the normal tension of the warp threads when said member moves in a iven direction said member bein movable in a direction opposite the given direction of movement under influence of the whip roll without lessening the normal tension of the warp threads.

In testimony whereof I have hereunto affixed my signature.

ELBRIDGE R. HOLMES. 

